Sasha Mordovets/Getty Images(WASHINGTON) -- President Obama's national security team is considering a significantly expanded air campaign over Syria to include long range bombers in addition to sea-launched Tomahawk missiles, ABC News has learned.

A senior national security official told ABC News that a U.S. military strike on Syria will do more damage to the forces of Syrian President Bashar al-Assad in 48 hours than Syrian rebels have done in two years of civil war.

Obama has repeatedly insisted that American involvement would be "limited." He has denied accusations that the United States is seeking to topple the Assad government, and the strike is intend to punish Syria for its alleged use of chemical weapons against its own people.

"I'm not itching for a military action," the president said at a press conference Friday.

The air campaign, which is expected to last at least two days, will potentially include an aerial bombardment of missiles and bombs fired by long range B-2 and B-52 bombers that would fly from the United States. The aircraft would be able to launch their munitions from outside of Syrian airspace because of the threat posed by Syria's large air defense system.

The use of aircraft gives planners flexibility in targeting Syrian resources that may have been moved in the two weeks since Syrian forces carried out a deadly chemical attack on a Damascus suburb that U.S. intelligence believes killed 1,429 civilians. The use of bombers would be in addition to an assault of Tomahawk cruise missiles fired from four Navy destroyers currently stationed in the eastern Mediterranean. Those ships are loaded with nearly 200 missiles. A U.S. official says plans call for firing the vast majority of those weapons.

Last week, U.S. officials said that initial planning for a limited U.S. military strike over Syria consisted only of the launch of sea-launched Tomahawk missiles.

There would be approximately 50 targets, mainly command and control centers for chemical weapons units, as well as artillery and missile systems used for chemical weapons delivery. The officials indicated that Syria's chemical weapons stockpiles would likely not be struck due to the risk that bombing them could release dangerous gases into the atmosphere..

During a congressional hearing Wednesday, chairman of the Joint Chiefs General Martin Dempsey said that the military is refining its target lists while the administration seeks Congressional authorization for a strike in Syria.

According to Dempsey military planners were focusing on "targets directly linked to the control of chemical weapons but without exposing those chemical weapons to a loss of security. Secondly, the means of delivery and the third, those things that the regime uses -- for example, air defense, long-range missiles and rockets -- in order to protect those chemical weapons or in some cases deliver them."

The nation's top military officer acknowledged that Syria has been moving its resources over the past two weeks, in some cases placing prisoners as human shields at potential target areas. He added that the movement of resources has also provided greater intelligence that has improved targeting.

Dempsey hinted at a broader air campaign at Tuesday's hearing before the Senate Foreign Relations Committee when he said "it won't surprise you to know that we will have not only an initial target set but subsequent target sets should they become necessary."

He also provided another hint when he told the House Foreign Affairs Committee on Wednesday that some countries in the region would indirectly support the limited strike through "basing and overflight."

When Dempsey was asked if Turkey had granted permission for the use of its airbases to the United States, Dempsey said he could only talk about that in a classified setting. He also volunteered the same would hold for questions about Jordan and other countries.

A U.S. official confirms that the White House is also considering a separate proposal to have the U.S. military begin training Syrian rebel fighters in Jordan. Currently the CIA is running a small training program for vetted Syrian rebel fighters there. The thinking is that the U.S. military could broaden that training. The official says the proposal had been presented prior to the discussion of a limited military strike against Syria and is not tied to the current congressional debate.